Methods for ionophorically screening pore forming bacterial protein toxins and receptors

Abstract

A method for determining the amount of live pore forming bacterial toxin protein in a sample is provided, the method including the steps of a) forming a membrane comprising a lipid bilayer and a receptor, b) contacting the membrane with an ion solution and the sample, c) measuring ion flow through the membrane, d) comparing the ion flow through the membrane to a standard curve, and e) determining the amount of pore forming bacterial toxin protein in the sample. A kit for determining the amount of live pore forming bacterial toxin protein present in the sample is also provided.

What is claimed is: 
     
       1. A kit for determining the presence of pore forming bacterial toxin protein in a sample, comprising:
 1) a receptacle comprising an aperture; 
 2) components for forming a lipid bilayer in the receptacle, such that the lipid bilayer spans the aperture in the receptacle and provides separation between two compartments, comprising:
 a) at least one lipid selected from the group consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS), 1,2-diphytanoyl-sn-glycero-3-phosphocholine, and cholesterol; and 
 b) a receptor specific for the pore forming bacterial toxin protein suspected of being in the sample, wherein the receptor binds the pore forming bacterial toxin protein and forms a pore in the lipid bilayer; 
 
 3) an ion solution; 
 4) a device for detecting ion flow through the lipid bilayer selected from the group consisting of radio isotopes, dyes, and a system for measuring electric current; and 
 5) instructions for determining the presence of pore forming bacterial toxin protein present in the sample. 
 
     
     
       2. The kit of  claim 1 , wherein the ion solution comprises a buffered physiological salt solution. 
     
     
       3. The kit of  claim 2 , wherein the ion in the ion solution is selected from the group consisting of Ca, K, Cl, Mg, and combinations thereof. 
     
     
       4. The kit of  claim 1 , wherein the receptor is provided in the form of a membrane containing the receptor. 
     
     
       5. The kit of  claim 1 , wherein the system for measuring electric current comprises electrodes and a meter. 
     
     
       6. The kit of  claim 1 , further comprising one or more controls. 
     
     
       7. The kit of  claim 6 , wherein the one or more controls comprises a further receptor to exclude false positives or demonstrate a positive kit response. 
     
     
       8. The kit of  claim 1 , further comprising a guide with control values for pore forming bacterial toxin proteins.